Helping Ghana cope with cancer
25 November 2015 Last updated at 00:52 GMT
It is estimated that more than 300m people now live away from the country of their birth and that they send back more than £500bn ($750bn) to their families.
For some developing countries the money sent home is a vital part of the economy, but many migrants want to do more than just ship back cash.
A growing number of those who have enjoyed success in their adopted homelands want to use the skills and experience to "give something back" to their country of origin.
Theadora Pepera is a British-based Ghanaian consultant gynaecologist, who is helping Ghana develop its cervical cancer screening programme.